A man claiming to be a leading Taliban negotiator in secret talks with Afghan officials was actually faking, The New York Times reported Tuesday in the latest setback to efforts to end the war.

A man claiming to be a leading Taliban negotiator in secret talks with Afghan officials was actually faking, The New York Times reported Tuesday in the latest setback to efforts to end the war.

For months, the high-level meetings backed by NATO appeared to be showing progress if only because of the purported participation of Mullah Akhtar Mohammed Mansour, one of the most senior Taliban commanders.

But it now seems the talks have achieved little and US officials have given up hope the man was either Mansour or even a Taliban leader at all, the Times said.

"It's not him," a Western diplomat in Kabul intimately involved in the talks told the newspaper. "And we gave him a lot of money."

NATO and Afghan officials told the Times that they had met three times with the fake Taliban leader, who came from Pakistan, where Taliban leaders have taken cover.

He was even flown to Kabul on a NATO aircraft and ushered into the presidential palace to meet with Afghan President Hamid Karzai, who has appealed to the Taliban to come to the negotiating table.

Low-level commanders are said to have already spoken to the government in Kabul.

But the hardline group's reclusive, one-eyed leader Mullah Omar last week dismissed reports of Taliban involvement in peace talks to bring an end to the bitter, nine-year conflict as "misleading rumours."

The Times report came as bomb attacks blamed on the Taliban killed four Afghan civilians and two foreign soldiers in eastern and southern Afghanistan on Monday.

Along with other militants linked to Al-Qaeda, the Taliban has been fighting a deadly guerrilla war against nearly 150,000 foreign troops.

US officials told the newspaper they doubted the impostor's identity from the beginning.

But after the third meeting with Afghan officials in the southern city of Kandahar, a man who had known Mullah Mansour -- who some say is only second-in-command after Mullah Omar -- said he didn't recognize him, an Afghan leader said.

But neither US nor Afghan officials have confronted the alleged faker and Afghan officials have even said they hope he will return to the talks.

Some officials told the Times the man may have been a fraud trying to enrich himself, while others suspected he may have been a Taliban agent or an individual sent by Pakistan's ISI intelligence service, which is said to publicly claim to hunt the Taliban but privately support the group at times.